1. Field of the Invention
This invention relates to a process for collecting continuous organic polymer filaments centrifugally ejected from the spinning nozzles of a spinning head rotating at a high velocity. More particularly it relates to a process for collecting the above filaments by quenching or rapidly coagulating them with an annular liquid surface around the spinning head to collect them in the form of multifilament yarns or a web of ejected filaments arranged in parallel in the weft direction.
2. Description of the Prior Art
For collecting centrifugally ejected filaments, various processes have heretofore been proposed such as those of Japanese patent application laid-open Nos. Sho 48-73,569 (1973), Sho 50-116,772 (1975), Sho 51-17376 (1976), etc. However, any of them is directed to a process for collecting the ejected filaments, whether they are continuous or discontinuous, in the form of a mat-like non-woven fabric. Further as other examples, processes for glass fibers have been proposed such as those disclosed in U.S. Pat. Nos. 3,032,813; 3,250,602; 3,357,807; etc. Although the above processes include a process for producing multifilament yarns, no particular consideration has been taken as to cooling of the ejected filaments, and contrarily there have been proposed even processes of heating the filaments with hot air or the like to thereby soften and stretch them into fine filaments. Further these processes include a process for further making a glass fiber mat or pack, or a mat reinforced by warp fibers, of the ejected glass filaments. However, none of the above examples are suggestive of a process described above in the field of the invention, that is, a process for collecting centrifugally ejected, continuous organic polymer filaments by quenching or rapidly coagulating them by an annular liquid surface around the spinning head to collect them in the form of multifilament yarns or a web of ejected filaments arranged in parallel in the weft direction.
In the case where glass fibers are produced from molten glass, the spinning temperature is very high, and in the case of centrifugal spinning, too, fibers are rapidly cooled and solidified. Thus, no particular cooling, of course, is necessary. However, in the case where organic polymer filaments are prepared according to centrifugal spinning process, the passageway of filaments ejected from the spinning nozzles till they are collected is so short unlike the case of usual melt-spinning processes that unless a particular means is taken, there may occur not only a fear of an interfilamentary cohesion or agglutination, but a fear that the molecular orientation of ejected filaments at the time of spinning is relaxed.
Further as to a process for producing a web of filaments arranged in parallel as wefts, from the ejected filaments (this web will be hereinafter abbreviated to "weft web of ejected filaments"), there are prior inventions made by us: Japanese patent No. 835,956 (Japanese patent publication No. Sho 51-9067/1976) (entitled: Process for continuously fixing arrangement of yarns); Japanese patent application laid-open No. Sho 53-35,074 (entitled: Process for producing a web of filaments arranged in parallel as wefts from ejected filaments according to high velocity, centrifugal spinning process); and Japanese patent application laid-open No. Sho 55-36331 (entitled: Process for producing a weft web of ejected filaments according to centrifugal spinning). Among these processes, there is a process of cooling the ejected filaments with water. We found, however, as a result of our studies on the ejected filaments produced by the above processes, that the thickness of the ejected filaments at the location where one ejected polymer filament, not yet solidified, is circumferentially approaching one end in the width direction, of the warp yarn or one selvage of the tape at the time of spinning is different from the thickness of the filaments at the location where one solidifying polymer filament has just been caught by the warp yarn or the tape and the resulting polymer filament is going to leave another end of the warp yarn or another selvage of the tape; namely the filament at the former location is thicker and the filament at the latter location is thinner than the average filament thickness; in addition, knobs sometimes form at the former location; thus the thickness of the filaments becomes non-uniform. Accordingly, in order to obtain ejected filaments having a uniform thickness, it is necessary to avoid the contact of the filaments with any solid material before they are sufficiently cooled and solidified. We found as a result of further studies that when the ejected filaments are caught only by a liquid surface and at the same time quenched or rapidly coagulated, followed by moving the filaments from the location where they are caught, then it is possible to obtain the filaments in a uniform thickness.
Further we found as a result of additional studies that if slight faults are allowable in the ejected filaments in the above case, a process is effective as a reliable process for collecting the filaments, wherein at least one adhesive warp selvage material which is provided on an annular form liquid surface prepared concentrically around the spinning head, and moved in the longitudinal direction, catches the ejected filaments at the same time when the filaments are caught by the surface of the liquid, and the filaments are successively moved from the location(s) where they have been caught, guided by the movement of the warp selvage material(s) and collected. However, even according to the above process, it is impossible to collect the ejected filaments in the form of continuous multifilaments.